The present proposal is for a continuation of a longitudinal study of children (a biracial population, ages 6-16 years) for whom influences of hormones on blood pressure are being examined. Twice yearly the children have had blood pressure and anthropometics measured, and overnight urine samples collected for measurement of aldosterone, adrenal androgens (AA), luteinizing hormone (LH), sodium, potassium, and creatinine. Rates of growth and the changes in blood pressure with age have been well characterized for this population. From the original observations, several differences were observed between racial groups; specifically, black children were found to consume less potassium, produce about 40% less aldosterone and have higher blood pressures than white children. It was observed that children with positive families histories of hypertension were more likely to have lower aldosterone-excretion rates. As part of the proposed continuation of longitudinal studies, the hypothesis would be tested that children with low-aldosterone levels are predisposed to higher blood pressures. Although black children had lower potassium intakes, cross-sectional data indicated that only part of the racial difference in aldosterone production was secondary to a lower intake of potassium (potassium is a known stimulus of aldosterone production). Subjects with known low-aldosterone production (blacks and whites) would have diets supplemented with potassium to test the hypothesis that blacks with low-aldosterone production have a reduced responsiveness to potassium when compared to white children with low-aldosterone. Families of children with potassium-resistant low-aldosterone production would be screened for evidence of low-aldosterone production, and segregation analyses would be performed to establish the mode of inheritance of the "low-aldosterone" phenotype. In cross-sectional studies, AA-excretion rates were positively related to blood pressure in subjects greater than or equal to 10 years of age, suggesting an important role for the adrenarche in determining blood pressure levels in young people. In future longitudinal studies the role of AA as well as gonadal hormones would be studied as more children reach adolescence (the current mean age of the cohort is 12.7 yr). In addition, to better distinguish the individual influences of adrenarche, gonadarche, and increases in body size on blood pressure, a series of patients where these phenomenon are dissociated would be studied.